There are two different kinds of depreciations that an investor needs to know when analyzing financial statements. Depreciation and Amortization are different in terms of applicability to the kind of assets and liabilities. Tangible assets like buildings, machinery, equipment etc., are depreciated, intangible assets like copyrights, patents, goodwill, capitalized costs etc. are all amortized. On similar lines, liabilities such as premium income, subscriptions etc. are all amortized as such liabilities involve inflow of revenue or income over a period of time. It is a useful concept, which allows accountants to apply the period concept in accrual-based financial statements.